fix(apiproxy,client): the list projection column becomes a seedable watermarked block

Review finding (PR #791): the column carried bare values (no seq), so the
client could not seed its value store without risking a stale list block
outranking newer push frames — and nothing consumed the column at all,
leaving cold titles absent after a restart. SessionSummary.projections is
now the same SessionProjectionsBlock as the history tail (values +
asOfSeq; attached rows cut the live registry, cold rows serve the cache's
identity-checked cachedSnapshot whose asOfSeq is the lowest served-row
watermark). SessionManager.refreshList seeds each row's block into the
per-session projection store via per-key apply — partial-baseline
semantics: an absent key never clears, and higher-seq-wins keeps stale
list blocks beneath push frames and tail baselines — so cold titles
surface in the sidebar without opening a session.

packages/client/runtime/src/client/sessions/manager.ts

@@ -212,6 +212,19 @@ export class SessionManager {
             session.handleBlank(s.blank)
             session.handleRunning(s.running)
           }
+          // Seed each row's projection baseline into the per-session value
+          // store (cold titles surface without opening the session). Per-key
+          // apply, not seed(): the list block is a partial baseline — the
+          // cold cache serves only version-matching keys — so an absent key
+          // must not clear; higher-seq-wins still keeps a stale list block
+          // from overwriting a newer push frame or tail baseline.
+          for (const s of result.value.items) {
+            const block = s.projections
+            if (block === undefined) continue
+            const store = this.projectionStore(s.sessionId)
+            const values = block.values as Record<string, unknown>
+            for (const key of Object.keys(values)) store.apply(key, values[key], block.asOfSeq)
+          }
         } else {
           this.listState = 'error'
           this.listError = result.error